Check subtitles against the rules studios follow
Drop the file and every line that breaks a rule is marked in the table with the number that breaks it — 51 chars, 22.1 cps, 0.6 s, overlap.
What is checked
The limits are the ones Netflix publishes and many studios follow: two lines at most, up to 42 characters a line and 20 characters a second for adult programmes, at least 5/6 of a second on screen and no more than 7, and no line still showing when the next one starts. Garbled letters and lines out of order are flagged too.
Korean, Chinese and Japanese are checked by their own limits — 16, 16 and 13 characters a line, and slower reading speeds — with Latin letters, digits and punctuation counting as half. The language is recognised from the text.
Fixing what it finds
The buttons above the table filter the lines by problem. Overlaps are fixed in one step with “Fix overlaps”; any line can be edited by clicking it — the text, the start and the end. If almost every line is marked, the cause is usually somewhere else: hearing-impaired notes make lines long, and a wrong frame rate makes them short.
Questions
- Do I have to fix everything it marks?
- No. The rules are for professional delivery; a fan subtitle with a few long lines plays fine. Overlaps and lines that end before they start are the ones some players and editors refuse.
- Which rules for children’s programmes?
- Studios lower the reading speed to 17 characters a second for children. The checker uses the adult limits; treat lines between 17 and 20 cps as borderline.